The present invention relates generally to the field of information processing utilizing optical discs and particularly to a high-efficient optical-disc-type apparatus allows a host computer to effectively and/or multitaskingly perform various information processing actions directly from optical discs so as to alleviate the heavy burden of a hard-disk drive in the process of information reproducing.
An optical disc or compact disc (CD) is made from a transparent plastic material with a thickness of about 1.2 mm that contains a protected thin metal film wherein pits (or depressions) are formed. The pits have light reflectivities different from the light reflectivity of nonpitted portions of the metal film, thus forming a series of 0s and 1s for digital storage of data. In production, a master disc is first developed from a glass disc coated with a uniform layer of photoresist material that is subjected to a series of exposures to a high-power energy beam or laser for forming various pits via the technology of photolithography. The master disc is then used to develop a nickel mother for use in stamping out multiple copies of the discs in transparent plastic material. Each of these is then coated with a thin metallic reflecting layer and then with a protective polymer coating on top of that. When reproducing the stored information, a low-power laser is used to sense the presence or absence of pits. Because a laser beam can be so focused, adjacent tracks of the spiral of pits need be no larger than 1.6 xcexcm. As a result, one side of a typical 120-mm (4.72-in) CD can have 20,000 tracks for holding a minimum of 500 megabytes of data which can easily store the text of a 20-volume encyclopedia, while both surfaces of a typical 133-mm (5.25-in) or a 89-mm (3.5-in) floppy disk are able to respectively hold only 1.2 or 1.44 megabytes.
Owing to the nature of their high storage capacity, optical discs are especially suitable for storing information requiring or taking large storage spaces, such as patent information, video data, and digital audio files. In addition to the floppy-disk version, software developers have recently produced the 120-mm read-only-memory CD (CD-ROM) version of executable software programs, such as IBM(copyright) OS/2 and Microsoft Windows(copyright) 95 for use in personal information processing apparatuses, such as desktop- or notebook-type computers.
Even though becoming increasingly popularly equipped in computers, a CD-ROM drive plays a much less significant role in information processing when compared with a hard-disk drive that utilizes the magnetic recording technology. This is because the currently available computers are designed to execute a program or software basically through reproducing the information stored on hard-disk drives, especially when the size of a program exceeds the storage capacity of a floppy disk. When sold to an end user, a software program for use in applications such as disk controlling, word processing, spread sheet, drawing, and presentation making, is compressedly stored on a plurality of floppy disks or an optical disc. Regardless of being either stored in floppy disks or an optical disc, a purchased software program needs to go through a tedious software installation process through which all program files are decompressedly copied to a hard-disk drive wherefrom the software program is then executed. In accordance with this conventional practice, the storage space of a hard-disk drive is quickly filled up. This not only incurs indirect cost in the expenditure of the hard-disk drive in addition to the purchased price of a software program to the end user, but eventually slows down the read-and-write operation efficiency of the hard-disk drive because any data files created are constantly rewritten, fragmentally relocated, and eventually scattered all over the hard-disk drive. Accordingly, a longer time is needed to find all of the data of a particular file. The only remedy currently available for this problem is to routinely run a hard-disk maintenance process in order to remove file fragmentation. Unfortunately, as more software programs or data files are stored on the hard-disk drive, the hard-disk maintenance process becomes more and more time-consuming, because it also involves relocation of the program files that occupy most of the space of the hard-disk drive but are never changed or altered throughout the entire life of their usage. Still there is another concern that a hard-disk drive is subject to nonphysical damages, for instance, such as program files being truncated or cross-linked due to improper assessing or writing during information reproducing or being infected by computer virus. As a result, a software program becomes corrupted; and, another tedious software installation process is again needed. All of these point to the fact that the currently available computers are designed to preform information processing by reproducing the information stored on hard-disk drives; and, this is not necessarily desirable.
Since a software program is mostly stored on a plurality of floppy disks for its distribution, an end user is routinely advised to make a set of backup copies because floppy disks are susceptible to physical and external damages. Inevitably, another disadvantage is incurred: a time-consuming process for making backup copies.
The need to install a purchased software to a hard-disk drive further incurs another problem: it is extremely difficult for software developers to stop or prevent illegal-copying of software. There are existing hardware-type protection devices and password-type protection approaches; but they are affordable only for high-price software programs with an aim of selling at most a few thousand copies for use in trading stocks or futures in real time, for instance. In contrast, volume software programs are sold in sealed envelopes. Once a sealed envelope is opened, an end user is assumed to accept the software license agreement set by a software developer; and, the software program is not returnable. Unfortunately, there is no practical way to prevent an end user from illegally coping such a software program. As the software developers producing high-volume and low-price software programs suffer from their products being illegally copied, the consumers lose their opportunity to try out a software program before purchasing.
In view of the disadvantages and problems mentioned hereinbefore, it is clear that currently available computers and optical disc or floppy-disk apparatuses are not designed to achieve their optimal potential. Owing to the nature of durability and storage capacity far superior to that of a floppy disk, an optical disc has a greater potential to become a memory storage medium for constructing a special type of apparatus to remedy the disadvantages currently encountered in the available information processing apparatuses. Thus, the main interest of the present invention is to design a high-efficient optical disc apparatus wherefrom software programs can be directly launched so as to eliminate tedious, time-consuming software installation and thus to offer an alternative of copy-right protection to software developers, as well as to alleviate the heavy burden of a hard-disk drive in information processing. Also essential for an information processing apparatus of this type is the feature of disc-loading and -unloading flexibility that allows a user to easily change or replace desired discs at will. In order to achieve the highest efficiency in information reproduction, any discs and thus disc positions should be readily accessible by at least one optical unit at any time. An optical read head should be able to travel from one disc to another, and its travelling should be limited to one-directional movement (either linear or circular) because multiple-directional or three-dimensional movement greatly slows down optical-read-head travelling efficiency. It is also highly desirable that an information processing apparatus of this type in accordance with the present invention comprises multiple disc sites each able to detachably hold a disc so that various software programs are readily available because Microsoft(copyright), WordPerfect(copyright), or Lotus(copyright) are most likely to produce their own software discs.
Multitasking or multiprocessing is another highly desirable feature for an information processing apparatus of this type in accordance with the present invention. In the context of the present invention, multitasking or multiprocessing is defined as referring to separate hardware control units that allow execution of separate or several software programs simultaneously. Because of containing a plurality of discs wherefrom several programs can be directly launched, an information processing apparatus of this type needs a safeguard device to prevent the discs stored therein from being unauthorizedly removed. Further, this type of information processing apparatus should be compact enough to be internally installed in a computer, because with the trend towards miniaturization, no future computers would be spacious enough for internally storing a bulky CD apparatus holding more than two horizontally spaced 120-mm discs.
An information processing apparatus of this type with all or a selected combination of the features mentioned hereinbefore is not yet readily taught by the prior arts. This is discussed as follows.
U.S. Pat. No. 4,644,515 describes a laser-disc digital data video storage system in which multiple discs stacked upon a common rotatable drive shaft are to be read by a plurality of stationary read head arrays for commercial use. This jukebox-like system allows multiple users to access its information by employing a huge number of read heads, for example 55,000 heads (or one head for each track), in each read head array. One of the main disadvantages of this type of system is its lacking disc-loading and -unloading flexibility; that is a user cannot access the common drive shaft for changing or replacing a desired disc at will. U.S. Pat. No. 4,888,751 describes an image information processing system in which (at least) an optical unit having an optical head arm rotatable through 180 degrees is used to scan the information stored on either adjacent side of multiple discs that are stacked at predetermined intervals on a detachable mounting mechanism. The detachable mounting mechanism provides some improvement in disc-loading and disc-unloading flexibility over U.S. Pat. No. 4,644,515 mentioned above, but is still inconvenient for a user to replace or change a desired disc at will due to the stacking nature of its disc arrangement. This prior apparatus is afforded with a plurality of optical units such that one of the optical units is most likely readily available for vertically moving to a next selected disc. In such a manner, the process of accessing information recorded on a different disc is speeded up; otherwise, the access time will be unacceptably slow since an optical unit in such a system has first to retract out of a disc space by swinging, to move vertically to a new disc space to be entered, and then to seek a new track by swinging. In this prior art, it is obvious that the presence of the multiple optical units is intended for speeding up disc-track access time between discs, but not for achieving any multitasking.
To improve the access time for reproducing the information stored on different discs, U.S. Pat. No. 5,189,652 describes a stationary-type optical disc apparatus that is characterized by a plurality of optical units each slidable into a disc space to access a predetermined position of a disc. Although it reduces the access time, this system neither affords disc-loading and -unloading flexibility referred to above because of its stationary and disc-stacking natures, nor provides any multitasking capability.
Instead of using the approach of stacking as used in the abovementioned prior arts, U.S. Pat. No. 4,722,078 employs a plurality of horizontally spaced disc compartments (or trays) each holding an audio disc which, upon selection, can be scanned by a disc playback module that is capable of being horizontally transported between the disc compartments. Because each disc compartment has a separate means for independently extending and retracting out of and into the apparatus, this audio CD player requires multiple front entrances. In other words, this configuration is too bulky and cannot be internally installed into the existing drive bays of current computers, which typically have dimensions of 146-mm (5.75-in) in width, 41-mm (1.75-in) in height, and up to about 254-mm (10-in) in depth. In addition, it lacks multitasking capability.
Other examples using the nonstacking approach are embodied in U.S. Pat. Nos. 5,146,451, 5,193,079, and 5,251,192. However, in accordance with these prior arts, discs are not readily accessible at any time because their disc-storage sites need to move to a predetermined position before a selected disc becomes accessible, thus slowing down information-reproduction efficiency. Similar inefficiency is also seen in U.S. Pat. Nos. 5,119,354 and 5,335,218 that utilize a disc transfer means comprising a drive roller to deliver a disc selected from a disc container or magazine (having a plurality of discs in a pile therein) to a disc drive for rotating and thus reading. Although improving disc-loading and -unloading flexibility referred to above, all of these prior apparatuses with capability of holding a plurality of discs require several additional transitional stages before a selected disc becomes accessible to a singular optical unit. These apparatuses are best for use in as-intended audio applications, not for use in information processing that requires high-efficient, high-speed information reproduction.
Providing disc-loading and -unloading flexibility to some extent; U.S. Pat. No. 5,043,963 provides an information processing apparatus capable of playing a disc selected from a plurality of sizes such as 80-, 120-, 200- or 300-mm in diameter. These multisized discs are laid on a tray wherein a circular-like section used to store a plurality of small-sized discs is rotatable for their selection. Different versions of apparatuses capable of playing optical discs with different diameters are seen in U.S. Pat. Nos. 5,119,354 and 5,253,235. The ability of playing the discs with different diameters is desirable, however, the discs in these prior apparatuses fail to be readily accessible by their single optical unit at any time.
In the conventional CD apparatuses, a single clamp device (or press member) capable of pivoting downwardly or upwardly is often used to pinch a disc mounted to a drive shaft or turntable for rotating. Clamp devices of this type are embodied in U.S. Pat. Nos. 4,722,078, 5,146,451, 5,251,192, and 5,253,235. Those are not suitable for use when a plurality of discs need to be in a readily-accessible state at any time. U.S. Pat. No. 5,375,113 describes a simple clamping mechanism for each of a number of turntables, which is desirable. However, it remains to be seen whether the clamping mechanism can provide necessary clamping force and at the same time can afford an easy release of a loaded disc. Accordingly, there is a need to design a simple, yet effective and space-saving disc-clamping device with disc-loading and -unloading flexibility for use in the information processing apparatus in accordance with the interest of the present invention.
In order to simultaneously launch several software programs directly from either an optical disc or multiple optical discs in accordance with the interest of the present invention, the hardware of an information processing apparatus must possess multitasking capability. This requires not only having a plurality of optical units but also a variety of signal process means (such as decoders), control means (including a plurality of microprocessors or a microprocessor with multitasking capability) and data transmitting means that all coordinately work together for reproducing plural sets of data simultaneously from various disc positions on a disc or on several discs and at the same time transmitting them to a host computer. Otherwise, optical units cannot be instructed to independently and simultaneously move to a plurality of predetermined disc positions plural sets of data retrieved from discs cannot can be simultaneously processed for returning back to their original state and then transmitted to a host computer. Thus, plural discs and optical units will make an information processing apparatus more efficient in terms access time, but will not necessarily arrive at any multitasking nature needed for future high-speed information processing. One example is exemplified in U.S. Pat. No. 5,375,113 which describes an apparatus that has a plurality of disc storage sites (in nonstacking form), each having a separate drive means and an optical disc situated together, for reading data specifically from one single, selected optical disc. The main object of the prior art is to eliminate much of the costly and duplicative hardware found in systems utilizing drive cartridges so that common control means such as latches, demultiplexers, and multiplexers are used in order to fulfill its main object for delivering a power signal to a selected single disc storage site for activating its drive means to read information from its respective disc. Even though various electronic configurations are given, the prior art utilizes only one single microprocessor for instructing which drive means should be turned on or which servo control device should be activated. Under the circumstances, it is not possible to simultaneously issue multiple commands or control signals to activate and thus to control a plurality of drive means for performing information reproduction from plural discs at the same time. In essence, the prior apparatus is specifically designed for information reproduction to take place one at a time in a selected disc storage site; thus, it lacks a multitasking capability. This is further substantiated in the fact that throughout the entire context, this prior art neither mentions nor even suggests retrieving information simultaneously from plural discs and sending plural sets of retrieved information at the same time to its host computer, which are all essential for multitasking to take place.
It is clear that each of the current CD apparatuses has its own merit but all suffer from various types of disadvantages, such as being unable to launch programs directly from optical discs, lack of multitasking capability, the inability for all discs and thus disc positions to be readily accessible with respect to at least one optical unit at any time, lack of disc-loading and -unloading flexibility, lack of flexibility for optical units to travel between discs, lack of an efficient means for an optical read head to selectively travel between discs, too bulky to be installed in a host computer, and/or lack of a device to safeguard optical discs from being unauthorizedly removed.
A primary object of the present invention is to provide an information processing apparatus with multitasking-capability hardware so that a plurality of optical units are capable of independently and simultaneously moving to a plurality of disc positions, making it possible to launch one or several software programs directly from the information processing apparatus, to provide true multitasking capability, to eliminate tedious and time-consuming software installation, to offer a kind of copy-right protection, and to alleviate the burden of a hard-disk drive in information reproduction processing.
Another object of the present invention is to provide an information processing apparatus with turntables having disc-loading and -unloading flexibility, wherein each turntable comprises a disc-holding and -releasing means with self-clamping and self-releasing feature for each optical disc.
Another object of the present invention is to provide an information processing apparatus with turntables and optical units being arranged in a particular manner, wherein each optical unit comprises an efficient driving means for moving at least one optical read head selectively between discs so that several optical read heads are able to independently move to a plurality of predetermined disc positions on the same disc surface of a selected optical disc for simultaneously retrieving a plurality of information stored thereon.
Another object of the present invention is to provide an information processing apparatus with turntables and optical units being arranged in a particular manner so that the same driving mechanism is used to move the optical read head of each of said optical units selectively between disc positions and between discs, for greatly improving information access efficiency when an optical unit needs to move between discs.
Another object of the present invention is to provide an information processing apparatus with a variety of control means (including a plurality of microprocessors or a microprocessor with multitasking capability) so that at least two optical units are able to work coordinately and simultaneously on separate portions of a software program, for greatly improving efficiency in information reproduction.
Another object of the present invention is to afford an information processing apparatus with a security means to safeguard the optical discs stored therein from being unauthorizedly removed.
Another object of the present invention is to provide an information processing apparatus with a plurality of disc compartments so that it is possible to replace an optical disc in one disc compartment while the other optical discs stored in another disc compartment remain operating.
Another object of the present invention is to provide an information processing apparatus with a control means to allow a disc to be scanned either at a constant angular velocity (CAV) method or at a constant linear velocity (CLV) method.
Another object of the present invention is to provide an information processing apparatus with at least one turntable that can accommodate an optical disc with different disc diameters, affording greater application flexibility.
The present invention improves the conventional information reproduction practice by providing an optical information processing apparatus with multitasking-capability hardware and disc-loading and -unloading flexibility means, thereby allowing a user to launch a software program or simultaneously a plurality of software programs directly from an optical disc or several optical discs stored therein. The multitasking-capability hardware of the present invention comprises a plurality of turntables, optical units, control means, signal-process means, and data transmitting means to coordinately work together for multitaskingly retrieving, controlling and transmitting a plurality of information simultaneously from various positions of a disc or several discs to a host computer. Turntables and optical units are arranged and rendered in a particular manner such that at least one optical unit can access any positions of at least two discs, a plurality of optical read heads situated in said optical units can independently and simultaneously access a plurality of positions of on the same surface of a disc for high-speed information processing; and/or a plurality of positions of separate disc surfaces for multitaskingly perform several programs at the same time. In accordance with the present invention, the number of optical units can be less as compared with that of turntables, for reducing the production costs of making an optical information processing apparatus while maintaining high efficiency in information reproduction.
An optical information processing apparatus of this type is optionally equipped with a plurality of disc compartments so that one disc compartment can be independently open for disc exchanging while the other disc compartment remains closed and active programs remain operating, with a disc holding means having self-clamping and self-releasing feature to facilitate disc-loading and -unloading operation, with at least one turntable capable of accommodating a disc with various disc diameters, with a control means to allow a disc to be scanned either at a constant angular velocity (CLV) method or at a constant linear velocity (CLV) method, and/or a safeguard mechanism.